AN OUTBREAK OF ACUTE INTOXICATIONS FROM CONSUMPTION OF INSUFFICIENTLY PROCESSED CASSAVA IN TANZANIA

An extensive outbreak of acute intoxications, with nausea and vomiting as major symptoms, occurred in a drought stricken district in southern Tanzania in 1988. Investigations revealed that these effects were due to cyanide intoxication from consumption of insufficiently processed cassava roots, the only crop to survive the drought. High plasma and urine levels of the cyanide metabolite thiocyanate support a high dietary cyanide exposure in the affected population. Due to food shortage the lengthy sun-drying normally used to remove cyanogenic glucosides from roots was replaced by repeated pounding and drying to obtain flour for consumption in one day. An experiment indicates that high residual levels of cyanohydrin, an intermediate breakdown product of the cyanogenic glucoside, was the principal source of dietary cyanide exposure. Cyanohydrins may be easily removed and toxic effects from cassava avoided by application of more effective tissue disintegration and drying techniques.